Ireland is a parliamentary, representative democratic republic and a member state of the European Union. While the head of state is the popularly elected President of Ireland, this is a largely ceremonial position with real political power being vested in the indirectly elected Taoiseach (prime minister) who is the head of the government.
The predominant religion in Ireland is Christianity, with the largest church being the Roman Catholic Church. Ireland's constitution states that the state may not endorse any particular religion and guarantees freedom of religion.
Favorite Irish drinks - "When in Rome ..." applies to any place in the world, really. Especially when it comes to food and drink. True, you can survive an Irish holiday on Big Macs and Coke (or Whoppers and Pepsi, for the sake of variety). But will you really have experienced the local cuisine? No - and going into a pub and drinking just Bud Light should be positively discouraged. If you want to down a few, why not try the local brew?